Packing-expander.



W. H. LIBBER.

PACKING BXPANDER APPLICATION FILED 213.20, 1911 1,019,262. Patented Mar. 5, 1912.

Fl3nii i av ATTEIRNEY.

UNI D ETATES PATENT- ermion WILLIAM H. IEBER, F MILWAUKEE, WISCONSIN, ASSIGNORTO ALLIS-CHALMERS COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF NEW JERSEY.

PACKING-EXPANDER.

To all iif'baa'g gconcemf 1 Be it known th 13' I, WI LIAM H. LIEBER,

' a'citizen ,of ,the United States, residing at Milwaukee,in the' county of Milwaukee and State of WYisconsin, have invented a certain new and useful Improvement in Packing Expanders, of which the following is a specification.

, This'invention relates to improvements in the construction of'packlng expanders par-.

ticularly adapted to be used-for expanding cup leather packings such 'as are universally used, for instance, in the brake cylinders of: air brakes." V

The object of the invention is to provide.

a packing expander which is simple in its construction, efficientin its operation, and

' which can easily and cheaply manufacturecl.

In using packing expanders for expandingcup shaped packings it has been found essential to have the expander coact along the greatenpa'rt 0fthe cylindrical portion ofithe packing. Several devices have been devised in which sutficientxcoaction between the expander and 'packingis obtained, but

these devices have been-diflicult tomanufac-l ture since they require either a special stock" or agreat amount of machining to produce A feature-oi the present invention is to form the expander fromfsheet metal and as much as-possible by the use of dies, there by eliminating to a great extent the constrjuctive difiiculties,

' For many years, packing, expanders for the cup leather packings used in brake cylindersof 'air' brakes, have consisted of a split ring formed of spring wire. This expander coacte'd-with the cup leather packmg near the bend thereof and was prevented from moving longitudinally of the cylindrical portion'of the cup leather by the piston follower which was provided with -an annular recess at its periphery adjacent the bend of the packing, to permit insertion of the expander ring. Thousands of air brakej pistons thus constructed-have been placed on the market and are at present in serv 1ee=- In order to provide a sheet metal packing expander whichis interchangeable with the old form ofspring wire packing expander Specification of Letters Patent.

jcess between the f so that the piston followers now in use may 'stillbe utilized, provision must be made for preventing the expander from moving longitudinally' of the cylindrical'portion of the cup leather due to the large recess formed 'in the follower and necessary withlthe'told form of expander ring. 4

It is an object of the present invention to provide a ring which will be locked against longitudinal shifting and which can be freely substituted for the'old form ofs'pring wireexpander. i

A" clear conception of several embodi- I Patented Mar. 5, 1912. Application filed February 20, 1911. Serial No. 609,645.

ments of the invention may be had by re-,

ferring to the accompanying drawing in which like'refere nce characters designate the same parts in like or different views, although the invention is not limited to the particular art selected to illustrate same.

Figure 1 is a fragmentary central vertical section through a brake cylinder, piston and piston packing. showing an expande r ring in position. Fig. 2 is a central vertical section through the packing expander ring shown in F ig. 1, the ring being expandeda maximum amount. Fig. 3 is a central vertical section through a modification-. of the packing expander ring, showing the ring expanded a maximum amount and showing also a modification of the formation of the ends of the;ring.

' The brake cylinder 2, the end of which is inclosed by the cylinder head 1, is bored to receive the continuous circular or cup shaped packing 5 composed ,of leather or other suitable material. The cup shaped packing 5 is clamped between the piston body 8 and the piston follower 3, the clamping of the packing 5 being along its fiat or plane portion. If it is desired to substitute a continuous cylindrical packing for the cup shaped packing 5 shown, such a substitute packing can be fastened to the periphery of the piston without coaction with the, follower 3. The follower 3'has asnialler Outside diameter than the interior diameter of the cylindrical portion 6 of the cup shaped packing 5, thus forming an annular space between these members. The portion of the follower 3 adjacent the piston and near the bend of the cup shaped packing 5 is cut away to form an annular groove or' reolllower and the piston.

-with an intermediate connecting portion.

The packing expander ring 7, which' is preferably formed of sheet metal, has a Z- shaped cross section and is discontinuous at one portion of'its periphery along end surfaces 9 formed parallel to the axis of the ring 7. By- Z-shaped section is meant any form having two substantially parallel legs The longer leg act the Z forming the cross section oft-he expander ring 7, is adapted to bear against the inner periphery of the cylindricalor free portion 6 of the packing 5. The remaining portion of the ring extends inwardly from the cylindrical leg 4 and has smaller. internal diameters than the outer diameter of the follower 3. The edge-of the portion of the ring having least diameter may either be turned outwardly as shown in Fig. 2, or inwardly. \Vhen the packing expander ring 7 is inserted between the follower 3 and packing 5, as shown in Fig. 1, the portion of the ring 7 having least diameter abuts with its free edge against the inwardly projecting portion of the 'packing 5. The portion of the ring 7' having smaller diameter should be formedof axial extent equal to the width 'of the groove or recess in the. follower, thus spanning" the annular recess and providing'mearis for preventing axial displacement of the ring 7 on the packing 5. The expander ring 7 is inserted within the piston, while the fol'- lower 3 is removed therefrom, by contracting the ring until the adjacent ends 9 nearly meet.- .The ring while in this contracted condition is inserted within the cylindrical portion 6 of the cup shapedpacking 5 until its port-ion of smallest diameter abuts against the radiaLportion of the packing 5. The expander ring 7 is then permitted to expand until the leg 4: of the Z coacts against the cylindrical portion 6, thereby expanding samefagainst the cylinder. wall.

In the modified form of ring, see Fig. 3,. the packing expander ring 17 is also formed with a Z-shaped cross section. The difierence between this construction and that disclosed in Fig. 2 isthat the portion of the ring having the smaller diameter is not turned outwardly along the edge which normally coacts withthe iiat-portion of the packing. With the ring 17 inserted within a piston the longer leg 14 of the Z section extends into-the space formed between the piston and follower and coacts against the inner periphery of the cylindrical or free portion 6 of the acking 5, while the edge 21 of'the shorter lb of the Z abuts against the flat portion of t e packing 5. The portion of the expander rin 17 of smallest diameter, as in the device disclosed in Figs. 1 and 2, again extends into the recess formed between the follower 3 and'piston, thereby preventing axial displacement of'the ring 17 upon thepacking 5. \The expander ring interior of the 17 is discontinuous at surfaces 19 which are parallel to the axis of the expander, and at surfaces angles tothe axis of the ring. tion of the ring 17'within a piston is accbmplishe'd in a manner similar to that of inserting the ring 7 The coaction of the-legs 4, 14, ofthe expanders'7, 17, with the cylindrical or free portion 6 of thecontinuouscircular packs ing 5, and the outward pressure exerted by the expander upon this cylindrical pon tion 6 of the packing, tends at all tim'esto keep the packing in coaction with. the bore of the cyl nder 2,'thereby producing a tight joint between the piston and cylinder. Since the fluid*pressure is admitted to'the packing 5 only, a further packing ofthe oint between the reciprocating piston and the cylinderis-provided by the fluid. pressureacting-iiiadhithe in- .terior surface of the, circular packin 5;" If

for any reason, the bore of the cy inder i is not perfectly'true, the. outer diameter 0:

'each other and thus tend to prevent bunch ing of the adjacent packin he rings can be forme H either by spin ning, rolling or-withthe use of dies, the lat ter method however being preferred. forming. the ex ander ring with the use dies, a strip 0 sheet metal of the corre length is rolled into the form of a discoi tinuousl cylin rical ringof the roper d ameter.- The'rjn thus formed 1s inserte on a stationary die having diameters corr sponding to the inner diameters of the fi: ished expander and also having a slot Whit receivesthe longer leg 4,14, of the rim The outer movable 'die, which may be eith continuous or sectional and has internal t ameters corresponding to the'external ameters ofthe portions of the expanderrit of smaller diameter, is then forced agaii the ring portion whic projects from 1 slotin the stationary die, pressing same i1 either of the forms illustrated. I

'The modified forni of.ring would'pn ably be easier to, form by meahs of dies th the form of 'ring shown in Fig."2,"althou the 'additidnal area of. cross sec'tiohbf ring shown in Fig. 2 would tend to-give t ring a greater degree of stiffness. 'It'sho' also be noted that either of the forms rings disclosed could be readily substitu ing locked against lpngitudinal shifting J the ring on the packing It should be understdod that itiis" not sired to. be limited 'to the exactdet ail:

construction shown and described, for. o"

20 which are formed at right The inser-' ous modifications will occur to a person skilled in the art.

It is claimed and desired to secure by Letters Patent, I

1; In combination with a continuous circular paglging having a cylindrical portion adapted" bear against the cylinder wall, a sheet-metal expander ringvfor said packing, said ring havin a cylindrical oi'tion adapted to bear directly against; sai cylindrical portion of'said packing, a second cylindrical portion of smaller diameter than said first mentioned portion, and a plane portion connecting said cylindrical portions of said ring.

2. In combination with a continuous circular packingjhaving a cylindrical portion adapted to'bear against the cylinder wall, a

sheet-metal expander ring forsaid packing,

said ring having a cylindrical portion adapt- V ed to bear directly against said cylindrical portion of said packing, a second portion of smaller diameter than said first portion adapted to coact against another portion of said packing, and a third portion connecting said portions of said ring.

' 3. In combination with a continuous circular packing having a cylindrical portion adapted to bear against .the cylinder wall and a plane portion extending inwardly from said cylindrical portion, an expander ring for said packing, said ring having a cylindricaliportion adapted to bear directly against amajor portionof said cylindrical,

portion of vsaid packing, a second cylindrical ring portion free from engagement with the cylindrical portion of said packing and coactlng with said plane portion of said packing, and third portion of said ring tantially plane portion connecting-said circular portions, one of said circular por tions coacting directly with said circular packing and extending between saidpac'king and follower, another-of said circular ring portions spanning said recess, and the plane portion of said ring coacting directly with said follower.

5. In combination, a piston, a follower adjacent said piston, said piston' and follower having a circular recess formed between them, a circular packing extendingaxially from said piston'and adjacent said follower, and a packing expander ring having .a plurality of circular portions and a connecting portion for said circular portions, one of said circular ring portions extending between said follower and said packing and bearin directly against said packing, another 0? said circular ring portions spanning said recess, and the connecting portion of said ring coact-ing directly with 'said :follower.

In testimony whereof, 'I aflix my signature in the presence of two witnesses.

WILLIAM H. LIEBER.

Witnesses:

CHAS. L. BYRON, Roe. E. S'roLL. 

